Visual sensitivity to parallel configurations of contours compared with sensitivity to other configurations

A role of rectangularity in perceiving a 3D shape of an object

“…These converging points are the vanishing points of the sets of line-segments of the object and they can provide additional information that is useful for recovering the veridical shape of the object (see the section "Geometry"). But, psychophysical results suggest that the visual system is not very sensitive to this kind of quantitative 3D information of the vanishing points (Dvoeglazova et al, 2021;Howard, 2012; see also Criminisi et al, 2005;Tyler, 2000;Li et al, 2014;Sawada & Pizlo, 2008). The perspective information improved human performance in recovering a 3D rectangular shape only a little (Attneave & Frost, 1969).…”

“…A perpendicular angle, which is formed by two line-segments in a frontoparallel plane, is processed faster by the visual system than a non-perpendicular angle (Feldman, 2007;Kubilius, Sleurs, & Wagemans, 2017). The sensitivity to a relative orientation between two line-segments in the frontoparallel plane is higher when the orientation is perpendicular (Koshmanova & Sawada, 2019;Dvoeglazova et al, 2021;Chen & Levi, 1996;Heeley & Buchanan-Smith, 1996;Nundy et al, 2000, see also Regan et al, 1996). On the other hand, the perception of the relative orientation between the line-segments is also biased toward being perpendicular (Carpenter & Blakemore, 1973;Bulatov et al, 2005;Nundy et al, 2000).…”

“…4 On the other hand, a rectangular shape is not perceived from an image that satisfies the conditions (JY′, JA′) but has large violations of the conditions (JY, JA) (Perkins, 1972, Perkins & Deregowski, 1982. This suggests that the visual system, primarily, uses the rules of orthographic projection for perceiving a rectangular shape and that it can also use the rules of paraperspective projection to some extent but note that the visual system is not very sensitive to such perspective information (see also Sawada & Pizlo, 2008;Dvoeglazova et al, 2021). This hypothesis was incorporated to develop a computational model that can recover the shape of a rectangular parallelopiped from a para-perspective image.…”

“…It was also possible that the retinal image of the square cylinder was so small that the perspective cue was not effective for perceiving the shape of the cylinder. The perspective cue might have been more effective on the shape perception it the retinal image of the cylinder were larger (Dvoeglazova et al, 2021). Even if the perspective cue was not effective, the unique recovery of the cylinder's shape was still possible on the basis of a Y-junction or an arrow-junction that was projected from a rectangular corner of the shape (Equation 1).…”

“…A rectangular corner is composed of three line-segments whose end-points meet at a vertex in such a way that each pair of line-segments forms a 90°angle. This specific angle, 90°, can also play an important role in the visual system (Koshmanova & Sawada, 2019;Dvoeglazova et al, 2021).…”